The present invention relates to a sawing gauge system to be used in case of intertrochantery accommodation osteotomies.
The large spongeous bone area available during intertrochantery accomodation osteotomies would suggest that a good reformatiom of the bone structure can be achieved. It still, however, can occur that the bone only heals slowly due to bone reabsorption in the osteotomy area. The bone reabsorption takes place as a result of micromovements on the contact surface and signalizes an insufficient interfragmentary compression.
The compression of the bone fragments is usually carried out with an angle plate aided by a plate clamp or according to the slotted slide plate principle. These methods cause the lateral cortical to be compressed as the plate is excentrically situated. The medial cortical is, on the other hand, under tension. In general, the principle of overbending of the plate is not taken into consideration. It is therefore a tension chord osteosynthesis.
There are numerous literature references as to how interfragmentary compression can be achieved during intertrochantery osteotomy. Following the method according to Buchner, the compression is achieved whilst the plate is being struck in due to an increasing distance between the razor socket and the osteotomy area. The renewed striking of the plate previously fixed in relation to the distal pressurizes the osteotomy area. In this connection, reference is made to an article in the journal "Orthopadie" No. 112 by G. M. Russ, published in 1974, pages 348-350. In another reference, "Die intertrochantere Osteotomie bei Coxarthrose" (Intertrochatery osteotomy by coxarthrosis) by R. Schneider published in 1979 by Sprinqer-Verlag, Berlin, the author recommends inclined osteotomy areas which then become compressed by screwing the proximal screw. In another reference, an article in the journal "Orthopadie" No. 122, published in 1984, pages 705-715, Heisel suggests that the principle of overbending of the plate according to Bagby be taken into consideration in order to prevent the osteotomy from splitting open on the medial side. Bagby describes the overbending of the plate in the case of shaft fractures. All these methods have the disadvantage, that their effectiveness cannot be assessed acurately and that some can cause considerable shear stressing.